<!DOCTYPE html>
<html lang="zh-cn">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>链接选择器演示</title>
    <style>
        a:link{
            color:black;
            text-decoration:none;
        }

        a:visited{
            color:orange;
        }

        a:hover{
            color:blue;
        }

        a:active{
            color:green;
        }

        /*focus伪类选择器*/
        input:focus{
            /*背景色*/
            background-color: skyblue;
            /*字体色*/
            color :red;
        }
    </style>
</head>
<body>
    <a href="#">演示链接</a>
    <br>
    <input type = "text" placeholder="请输入密码">
</body>
</html>